Shock absorbers are utilized to provide piston dampened movement between a lower unsprung mount and an upper sprung mount of a vehicle suspension. In some usages, the unsprung wheel spindle is supported with respect to the vehicle body by suspension components that provide the entire guided movement of the wheel spindle during vehicle jounce and, in those instances, "shock absorber" is the only term utilized to define this type of shock absorbing device. In other usages, the shock absorbers cooperate with other components connected to the wheel spindle to provide the guiding movement as well as dampening vehicle jounce and, in those instances the shock absorbers are referred to as "struts". For purposes of the present application, both of these types of usages will be referred to merely as "shock absorbers" and it will be understood that such terminology refers to both types of dampening devices.
Vehicle shock absorbers and other cylinder devices are disclosed by U.S. Pat. No. 4,828,231 Fukumara et al.; U.S. Pat. No. 4,890,822 Ezure et al.; U.S. Pat. No. 4,928,799 Zschiesche; U.S. Pat. No. 4,934,669 Bourdeau et al.; U.S. Pat. No. 5,070,970 Johnston et al.; U.S. Pat. No. 5,295,563 Bennett; U.S. Pat. No. 5,344,125 Cotter; U.S. Pat. No. 5,454,550 Christopherson; and U.S. Pat. No. 5,595,268 Paton.